In the 1940s, CDFW transported nuisance beavers from Stanislaus and Merced counties and released them within the South Coast Bioregion (+Mojave River). In 2013, it was proposed that these beavers were native to the South Coast Bioregion (+Mojave River). Since then, a reevaluation by multiple experts found their evidence supporting this proposal insufficient to support their novel claim: the evidence does not meet the logical standards to overturn the traditional understanding that beavers are non-native and are the sole result of introductions. My study found that beavers were not recorded for 110yrs by all the experts, until after the introductions. Also, although beavers are often heralded as ecoengineers benefiting wetlands and increasing biodiversity, in the South Coast Bioregion and Mojave River upper watershed they modify environments that disfavor four federally endangered species (two proposed): steelhead-southern populations, Santa Ana speckled dace, arroyo toad, and pond turtle. I will discuss the negative effects of beaver impoundments. Ultimately, how the beavers in the South Coast Bioregion (+Mojave River) are officially recognized by resource agencies, native or introduced, will have direct and significant implications on beaver management in the future by the agencies tasked with the recovery of at-risk species and restoration of ecosystems.